• Korean Journal of Plant Resources
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• v.23 no.4
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• pp.386-392
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• 2010

This study was done to measure the color and catechins contents in processed teas using the whole bands (400~2500 nm) with near-infrared spectroscopy(NIRS). The powder colors of 109 processed teas were measured with a colorimeter. The a/b ratios in Hunter color scale in processed teas accounted for about 98.9% of the variation in the fermentation degree(FD), indicating that the a/b ratio was a very useful trait for assessing fermentation degree. Also tea powders were scanned in the visible bands used with NIRSystem. The calibration equations for powder colors were developed using the regression method of modified partial least squares(MPLS) with the internal cross validation. The equations had low SECV (standard errors of cross-validation), and high $R^2$ (coefficient of determination in calibration) values with 0.996~1.00, indicating that the visible bands(400~700 nm) with NIRS could be used to rapidly measure the variables related to powder color and fermentation degree. Also another powders of 137 processed teas were scanned at 780~2500 nm bands in the reflectance mode. The calibration equations were developed using the regression method of MPLS with the internal cross validation. The equations had low SECV, and high $R^2$ (0.896~0.983) values, showing that NIRS could be used to rapidly discriminate the contents of EGC($R^2$=0.919), EC(0.896), EGCg(0.978), ECg(0.905) and total catechins(0.983) in processed teas with high precision and ease.

• Journal of Life Science
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• v.27 no.4
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• pp.476-481
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• 2017

Polyphenols are secondary metabolites produced by higher plants and have been used as antiallergic, anticancer, antihypertensive, antiinflammatory, antimicrobial and antioxidant agents. They are generally divided into flavonoids and non-flavonoids. The antimicrobial activity of flavonoids are stronger than that of non-flavonoids. The skeleton structures of flavonoids possessing antimicrobial activity are chalcone, flavan-3-ol (catechin), flavanone, flavone, flavonol and proanthocyanidin. The flavonols are shown antibacterial activity against several gram-positive bacteria (Actinomyces naeslundii, Lactobacillus acidophilus and Staphylococcus aureus) and gram-negative bacteria (Fusobacterium nucleatum, Porphyromonas gingivalis, Prevotella melaninogenica and Prevotella oralis). Among of non-flavonoids, caffeic acids, ferulic acids and gallic acids showed antimicrobial activity against gram-positive (Listeria monocytogenes and S. aureus) and gram-negative bacteria (Escherichia coli and Pseudomonas aeruginosa). These are found to be more efficient against the E. coli, L. monocytogenes, P. aeruginosa and S. aureus than antibiotics such as gentamicin and streptomycin. The kaempferol and quercetin showed synergistic effect with ciprofloxacin and rifampicin against S. aureus and methicillin resistant S. aureus (MRSA). Epigallocatechin gallate (EGCG) acts synergistically with various ${\beta}-lactam$ antibiotics against MRSA. In particular, the epicatechin, epigallocatechin (EGC), EGCG and gallocatechin gallate from Korean green tea has antibacterial activity against MRSA clinical isolates and the combination of tea polyphenols and oxacillin was synergistic for all the clinical MRSA isolates.

• Journal of the Korean Society of Food Science and Nutrition
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• v.24 no.2
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• pp.299-304
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• 1995

Antioxidative effect of tea extracts from green tea(steamed, roasted), oolong tea and black tea was investigated. Antioxidative activities of the crude catechin fraction were the most effective in oolong tea which contained the highest level of (-)-epigallocatechin gallate(EGCg). The water-soluble fraction obtained from oolong tea exhibited binding with more ferrous than copper ions. It showed a synergistic effect when used with an antioxidant such as BHT(0.5mg) and $\alpha$-tocopherol(2mg). Especially, this synergistic effect was exhibited more with BHT than with $\alpha$-tocopherol. Also steamed green tea, roasted green tea and oolong tea showed remarkable free radical scavenging action. The SC50(the concentration of a water-soluble fraction which is required to scavenge 50% of 100$\mu$M 1, 1-diphenyl-2-picryl hydrazyl radicals) of steamed and roasted green tea, oolong tea and black tea extracts were 11.3$\mu\textrm{g}$/ml, 11.4$\mu\textrm{g}$/ml, 12.7 $\mu\textrm{g}$/ml and 14.9$\mu\textrm{g}$/ml, respectively. It is assumed that the antioxidative activity of tea extracts is due to inhibition of peroxidation free radical scavenging and binding action of ferrous ions by mainly tea polyphenol compounds.

• The Korean Journal of Community Living Science
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• v.19 no.1
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• pp.55-61
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• 2008

This study was conducted to compare the nutrient and chemical contents of traditional Chungtaejeon tea with that of green tea which was harvested in Jangheung, Jeonnam district. Vitamin C, amino acids and total nitrogen contents of Chungtaejeon tea were lower than that of green tea by 0.30, 2.30 and 4.20g/100g, respectively. The tannin, caffeine, reducing sugar and chlorophyll contents in Chungtaejeon tea were the same as those in green tea. Comparing catechin contents, catechin (C), epicatechin (EC), and epigallocatechin (EGC) in Chungtaejeon tea were lower than those of green tea. However, gallocatechin (GC), epicatechin gallate (ECG), epigallocatechin gallate (EGCG) and catechin gallate (CG) showed no significant difference between Chungtaejeon tea and green tea. The flavonoid contents of Chungtaejeon tea and green tea showed higher quercetin and kaempferol contents in green tea, and higher myricetin content in Chungtaejeon tea. The measured amino acid contents for threonine and aspartic acid were lower, and for glutamic acid were higher in Chungtaejeon tea compared with those in green tea. However, free amino acid content in Chungtaejeon tea and green tea showed no significant difference. Potassium and magnesium contents in Chungtaejeon tea were lower compared to green tea but no significant difference was found for iron, manganese or calcium contents when comparing the two teas.

• Journal of Life Science
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• v.10 no.2
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• pp.202-209
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• 2000

The factors affecting chemical composition of green tea (Camellia sinensis L.) during extraction process were temperatures and times. The optimum extraction conditions were measured in relation to the changes of chemical compositions from water extracts of green tea (Camellia sinensis L.) under different extraction temperatures (50, 70, 9$0^{\circ}C$) and extraction times (1, 3, 5 minute). The change of color intensity during browning reaction, flavonoid components, contents of total phenols and hydrogen donating activity (reducing activity for $\alpha$, $\alpha$'-diphenyl-$\beta$ -picryhydrazyl) of water extracts form green tea increased as extraction temperatures increased from 50 to 9$0^{\circ}C$ and extraction times prolonged from 1 to 5 min. The contents of important free sugars such as sucrose and glucose slightly increased as the extraction time was prolonged, while little difference in the content of fructose with the prolonged extraction time. Catechins contents extracted from the commercial steamed green tea were increased at higher temperature and longer extraction time. Epigallocatechin (EGC) extracted from 9$0^{\circ}C$ (extraction time 5 min). presented 99.9 mg/g in highest composition of catechin followed by epigallocatechin gallate (EGCg), epicatechin (EC), epicatechin gallate (ECg). The content of vitamin C extracted from green tea was increased about 2 times as the extraction temperature increased from 50 to 9$0^{\circ}C$ and as the extraction time increased from 1 to 5 min. with exception at 9$0^{\circ}C$(extraction time:5 min) which showed less vitamin C content than 7$0^{\circ}C$(extraction time : 3 min) probably due to possible destruction of vitamin C by high temperature.

• Journal of the East Asian Society of Dietary Life
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• v.18 no.3
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• pp.391-396
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• 2008

This study was carried out to help restore and spread broaden the consumption of Chungtaejeon, a our traditional tea, Chungtaejeon in Korea, and as well as to gather the basic data on Chutaejeon tea. We have also compared the various ingredients components and physiological activities of Chungtaejeon tea extracts with that of green tea extracts. According to the results, the total phenol contents in of the Chungtaejeon and green tea extracts were 90.56 and 98.70 mg/100 mL, respectively, and their tannin contents levels in Chungtaejeon and green tea extracts were 214.14 mg/100 mL and 259.60 mg/100 mL, respectively, showing a difference in content. The catechin contents of the Chetaejeon and green tea extracts were in the order of EGC($15.80{\sim}16.50\;mg/100mL$), EGCG($10.40{\sim}10.60\;mg/100 mL$), and ECG($9.55{\sim}9.88\;mg/100 mL$), however, with the exception of EC(7.86 mg/100 mL) in the green tea extracts, there were not significant differences between that in them Chetaejeon and green tea extracts. Quercetin was the main flavonoid ingredient component in those both the Chungtaejeon and green tea extracts was quercetin, at levels of 0.08 mg/100 mL and 0.06 mg/100 mL and its contents in Chungtaejeon and green tea extracts were 0.08 mg/100 mL and 0.06 mg/100 mL, respectively. The primary amino acid in both tea extracts was theanine main amino acid at levels of, theanine contents were most increased in 8.02 mg/100mL and 10.80 mg/100 mL, respectively, Chungtaejeon tea extracts by 8.02 mg/100 mL and green tea extracts by 10.80 mg/100 mL. And the arginine contents of the Chungtaejeon and green tea extracts in Chungtaejeon and green tea extracts were 1.78 mg/100 mL and 1.86 mg/100 mL, respectively. In terms of mineral composition, potassium content was highest contents in the Chungtaejeon and green tea extracts by 19.80 and 18.04 mg/100 mL, respectively. Finally, the Chungtaejeon tea extracts offered the greatest anti-oxidation and ACE inhibition activities were most increased in the Chungtaejeon tea extracts, and the green tea extracts showed the highest level of nitrite radical scavenging activity at 90% was extremely much increased in the green tea extracts by 90%.

• Food Science and Preservation
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• v.24 no.1
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• pp.93-99
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• 2017

Collagen synthesis is decreased and matrix metalloproteinase-1 (MMP-1) levels are increased in naturally aged human skin, and these alterations cause changes such as skin wrinkling and decreased elasticity. As a part of our ongoing search for bioactive ingredients, MMP-1 inhibitory and type-1 procollagen synthesis inducing activities of aqueous methanolic extract of manufactured gambir product from Uncaria gambir were investigated in in vitro bioassay systems. In addition, total phenolic contents were quantified using a spectrophotometric method. Among tested samples, 40% MeOH eluate from 80% methanolic extract of manufactured U. gambir using open column chromatography packed with Diaion HP-20 resin showed significant MMP-1 inhibitory activities with an $IC_{50}$ value of $15.6{\pm}1.3{\mu}g/mL$. Furthermore, type-1 procollagen synthesis promoting property of 40% MeOH eluate ($IC_{50}$ value; $6.9{\pm}0.7{\mu}g/mL$) from 80% methanolic extract of manufactured gambir was higher than other eluates. Additionally, the present investigation revealed that 40% MeOH eluate of manufactured gambir product contained a high level of total phenolic compounds. The result suggests a distinct relationship between anti-wrinkle activity and total phenolic contents, and manufactured gambir product could be considered a new effective source of natural bioactive ingredients. Systematic investigation of manufactured gambir product will be performed for further development of its biological properties.